This invention relates to dyestuffs which contain an amino or acylated amino naphthol di-sulfonic acid radical and at least one phosphoric or phosphonic acid group and which are suitable for reactively dyeing cellulosic materials, e.g., cotton and cotton/polyester blends.
A process for reactively dyeing a hydroxy-substituted organic polymer, such as cellulose, is described by Stanford Research Institute in German Pat. No. 2,324,809, published Dec. 20, 1973. The process so described involves treating the cellulosic material with a dye containing a phosphonic acid group in the presence of a carbodiimide, e.g., dicyandiamide, in such a way that the dye is fixed to the cellulose in the form of a cellulose ester of phosphonic acid. The process can be illustrated by the following reaction: ##STR2## wherein R is a chromophore group, R'OH represents cellulose, CDI is the carbodiimide and CDIM is a residue or side product of carbodiimide. A similar mechanism applies for dyestuffs containing phosphoric acid groups. Cellulose materials so dyed exhibit good color stability when subsequently treated with alkaline detergents.
It is a primary object of the present invention to provide new fiber reactive dyestuffs which are especially suitable for coloring cellulose-based textile materials in the manner described in the above-mentioned German patent.
Still another object of this invention is to provide dyestuffs which may be employed in acid, neutral or alkaline baths to color cellulose materials.
These and other objects of the present invention will be apparent from the following description.